Interest in fuel cell batteries as power sources for portable electronic devices has grown. A fuel cell is an electrochemical cell that uses materials from outside the cell as the active materials for the positive and negative electrode. Because a fuel cell does not have to contain all of the active materials used to generate electricity, the fuel cell can be made with a small volume relative to the amount of electrical energy produced compared to other types of batteries.
In some types of hydrogen fuel cells, hydrogen is formed from a hydrogen-containing fuel supplied to the negative electrode side of the fuel cell. In other types of hydrogen fuel cells, hydrogen gas is supplied to the fuel cell from a source outside the fuel cell. A fuel cell system can include a fuel cell battery, including one or more fuel cells (e.g., a fuel cell stack), and a fuel source, such as a fuel tank or a hydrogen generator. Hydrogen generators that supply hydrogen gas to a fuel cell can be an integral part of a fuel cell system, or they can be removably coupled to the fuel cell system. A removable hydrogen generator can be replaced with another one when the hydrogen containing materials have been consumed. Removable hydrogen generators can be disposable (intended for only a one-time use). Both removable and permanently installed hydrogen generators can be refillable (intended for use multiple times) to replace consumed fuel composition.
Hydrogen generators can produce hydrogen using a variety of hydrogen containing materials and a variety of methods for initiating the hydrogen generating reactants. For example, hydrogen gas can be released when a hydrogen-containing material is heated, when a hydrogen-containing material reacts with another reactant, or when a hydrogen-containing material comes in contact with a catalyst.
A hydrogen generator is generally sealed to prevent leakage of hydrogen gas to the external environment, and hydrogen gas is released in a controlled manner to the apparatus being supplied with hydrogen. Hall of the hydrogen gas is not released as it is produced, pressure can build up within the hydrogen generator. To provide the maximum quantity of hydrogen and avoid unsafe leakage, it is desirable for the hydrogen generator to remain sealed during use. For hydrogen generators with replaceable cartridges of hydrogen-containing material or other reactants, means of access to the hydrogen generator to replace cartridges must therefore be restricted. To prevent leakage of hydrogen gas as a result of deformation or damage to sealing components due to the internal pressure, the hydrogen generator can be made from materials that are resistant to the expected internal pressures. However, this can require using heavier or thicker components or expensive materials.
In view of the above, an object of the present invention is to provide a hydrogen generator that will remain sealed during use and withstand the expected internal pressures, while having a simple design that is easy and economical to manufacture.